A 24-week, randomized, double-blind, placebo-controlled study to assess the tolerability and preliminary safety of subcutaneos (SC) dosing of r- metHuLeptin as compared with placebo in subjects across a range of doses and body mass indexes. The study will also assess the pharmacodynamic effects and preliminary efficacy across a range of subcutaneous doses of r-metHuLeptin by evaluating changes in body weight and body composition, comparing subjects treated with r-metHuLeptin to those treated with placebo. Also, the preliminary effects of r-metHuLeptin on the metabolic profile of subjects will be evaluated by examining changes in fasting and stimulating glucose and insulin levels, and in fasting lipid levels. Also, the pharmacokinetic and immunogenic profile of r-metHuLeptin will be determined.